Overview
Allergic rhinitis literally means "allergic nose inflammation": rhino means "to do with the nose" and the ending -itis simply refers to inflammation. Seasonal allergic rhinitis is also commonly known as "hay fever."
This condition can either be seasonal or year-round. In most people, an allergen - something that triggers an allergy - sets their symptoms off at about the same time each year. Spring attacks are usually due to tree pollen, while grass pollens dominate in the summer and weed pollens in the autumn. Most people with allergic rhinitis are sensitive to more than one allergen.
Perennial allergic rhinitis appears year-round. This condition is most common in people with allergies to allergens that are present all year. Naturally, people who are allergic to house dust mites or to their own pets tend to suffer no matter the season.
Causes
Hay fever is an atopic or allergic disease like asthma, meaning that the body tends to overreact to certain types of outside substances. One way it overreacts is by releasing histamine, a chemical present in many important animal cells. Histamine is a major cause of the symptoms of hay fever including sneezing, runny nose, and even coughing. Hay fever, like asthma, can be inherited, but you probably don't inherit particular allergies, such as to cat dander or ragweed. Instead, you just inherit the tendency to be allergic. Children have a 30% chance of developing allergic rhinitis if one of their parents is affected and a 50% chance if both have allergic rhinitis.
Symptoms
Hay fever is so common that almost everyone recognizes the basic symptoms: runny nose, sneezing, itching and congestion. Other symptoms of this seasonal form of allergic rhinitis include tearing of the eyes, coughing, and headache.
You can usually tell hay fever from perennial rhinitis by the fact that it appears at the same time each year. Another difference is that, while hay fever often causes red eyes, perennial rhinitis tends to leave the eyes alone. Perennial rhinitis can also cause minor blockage of the ears, particularly in children.
Treatment
Treating and preventing allergic rhinitis are often the same thing - the best way to cure the symptoms is to avoid the allergen. This may mean changing your habits, or even giving away a pet or moving to another house if the symptoms are unbearable and don't respond to medications. If the allergen is something you can't completely avoid, like dust mites, here are some steps you can take to make your home a haven:
- Remove furniture that collects dust (e.g., carpets, draperies, and stuffed chairs).
- If possible, use central air conditioning during high pollen and mould times.
- Put special dust mite covers on mattresses.
- Wash floors frequently with a wet mop.
- Reduce air humidity with a dehumidifier to maintain indoor humidity around 40% to 45%.
- Install a high-efficiency air filter called a HEPA filter.
- Use fungicide (e.g., equal parts household bleach and water) on sinks, shower stalls, vegetable storage areas, and garbage pails.
- Remove houseplants (a common source of mould).
If these measures prove insufficient, most people fortunately do respond to medications. The therapy of choice is antihistamines taken orally or as a nose spray. Your doctor or pharmacist can help you choose the medication best suited to your needs. For example, many oral antihistamines are now "non-drowsy." People with certain medical conditions (e.g., glaucoma, prostate problems) should consult their doctor before using antihistamines. It is important to know that some products contain antihistamines plus decongestants for symptom relief. Again, seeking advice from a health professional is recommended as those with medical conditions such as high blood pressure and diabetes must use caution with these types of medications.
A corticosteroid nose spray can be tried if antihistamines aren't working. Corticosteroid sprays are preferred if rhinitis symptoms are chronic. For seasonal allergies, some people may find that nasal sprays, eye drops, and inhalations containing sodium cromoglycate* are effective in preventing allergic rhinitis if treatment is started before allergy season and used on a regular basis. This type of treatment is usually less effective than antihistamines and corticosteroids. Women who are pregnant or breast-feeding should consult their doctor or pharmacist before beginning treatment for allergic rhinitis.
If allergen avoidance and medical treatment for hay fever aren't effective, a good option is allergen immunotherapy. Allergen immunotherapy may be referred to as desensitization, hyposensitization, or simply, allergen shots. Small amounts of the allergen are injected regularly, slowly increasing the dosage. The hope is that the immune reaction becomes weaker and weaker. Allergy shots are initially given one or two times each week. After about six months of weekly shots, maintenance treatment is started. Maintenance shots are usually given just once each month. After three to five years, some people can to stop getting shots.
Allergen immunotherapy isn't risk-free. Rarely, the person may have a system-wide immune reaction called anaphylaxis, which can be fatal. People receiving allergen immunotherapy have to wait in the clinic with a physician present for half an hour after each shot in case there is a reaction. The best time to start desensitization is at the end of the annual allergic period.
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For more information on brand names, speak with your doctor or pharmacist.
Other tips:
The important thing to remember about allergic rhinitis is exactly when the symptoms appear and disappear. Knowing these dates will give your doctor or allergist vital clues as to what's provoking the symptoms, and makes diagnosis easier.
By getting the details of where you live and work and when you suffer most, a doctor or an allergist can make a very short list of possible causes. Allergists use small, standardized doses of all the most common allergens to narrow down the diagnosis. They test for allergy by gently scraping the skin with each of these until they get a small rash. Most of these tests are nearly painless.
If none of the skin tests produce results, it's probably some other kind of rhinitis. These other conditions can be confused with hay fever:
- Vasomotor rhinitis: the nasal mucous membrane swells up with increased blood flow, causing runny nose and congestion, but typically no itching. There's no specific cause - patients aren't allergic to anything - although smoke, dry air, temperature change (such as coming in from the cold), and odours can trigger symptoms.
- Chronic rhinitis: may be prolonged symptoms of a common cold or another condition (e.g., low thyroid function).
- Rhinitis medicamentosa: caused by overusing nasal spray decongestants, which actually may increase congestion if used for more than about 5 days. Cocaine users are also vulnerable to this form of rhinitis.
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